Priority queuing in Simple Switch

[tuananh01]

Hello everyone,

I'm using the latest Development VM released in April.
I've read the BMv2 Simple Switch article and also looked into the multiqueuing.p4 example. They all said that if I want to use multiple priority queues, I have to uncomment the line:
#define SSWITCH_PRIORITY_QUEUEING_ON

But when I go to the simple_switch.h file at the directory /home/vagrant/behavioral-model/targets/simple_switch, I can't find the above line, what I saw is in the following image:

So my question is do I need to type the line #define SSWITCH_PRIORITY_QUEUEING_ON like you see in the image, then compile and install bmv2 again to use the feature?

Also when I scroll down, I see this:

Am I supposed to changes the `default_nb_queues_per_port = 1 to another value? Does changing this value has the same effect as I use multiple priority queues?

Thanks!

`

[jafingerhut]

See my answer here: https://forum.p4.org/t/priority-queueing/743

If the p4-learning repo uses source code of the p4lang/behavioral-model repository after the enhancement was made, I would recommend updating the instructions in this repo, since changing the source code and recompiling is no longer necessary.

[edgar-costa]

Hi @jafingerhut!

Thanks for the info. I will have a look at it and update it as soon as possible.

[WigginsLi]

How can i add the -- --priority-queues 8 in p4app.json or somewhere?

---

i simply modify the /<path to p4-utils>/p4utils/mininetlib/node.py as below and reinstall p4-utils. It works.
Is there a easy way to allow user to add custom options to simple_switch?

def add_arguments(self):
        """Adds arguments to the simple switch process"""
        args = [self.sw_bin]
        for port, intf in list(self.intfs.items()):
            if not intf.IP():
                args.extend(['-i', str(port) + '@' + intf.name])
        if self.pcap_dump:
            if self.pcap_dir:
                args.append('--pcap=' + self.pcap_dir)
            else:
                args.append('--pcap')
        if self.thrift_port:
            args.extend(['--thrift-port', str(self.thrift_port)])
        if self.nanomsg:
            args.extend(['--nanolog', self.nanomsg])
        args.extend(['--device-id', str(self.device_id)])
        if self.json_path:
            args.append(self.json_path)
        else:
            args.append('--no-p4')
        if self.enable_debugger:
            args.append('--debugger')
        if self.log_enabled:
            args.append('--log-console')
/*modify begin*/
        args.extend(['-- --priority-queue', str(8)])
/*end*/
        return args

[edgar-costa]

Hi @WigginsLi,

I recently added the option.

This p4-learning example already uses it (just check the readme or the topology files):
https://github.com/nsg-ethz/p4-learning/tree/master/examples/multiqueueing